CYLINDER HEAD FOR A FOUR STROKE COMBUSTION ENGINE

Abstract: The invention relates to a head (1) of cylinder (2) for a four stroke combustion engine with a valve gear with lifting valves. The head (1) of each cylinder (2) is provided with one main conduit (3), annular shaped orifice (4) leading into the cylinder (2) its axis (5) being situated in the direction of the main axis (6) of cylinder (2) and orifice (4) of main conduit (3), provided with interior valve seat (8) and exterior valve seat (9). Inside the interior valve seat (8) and exterior valve seat (9), in its closed position an annular plate (12) is situated of the sole lifting valve (7) of cylinder (2) provided by at least one stem (11). The main conduit (3) in the head (1) is divided into an inlet conduit (15) and exhaust conduit (16), where the inlet conduit (15) is provided with a valve (17) and/or with a slide valve (18).

Description: Cylinder head for a four stroke combustion engine. Technical field This invention relates to a cylinder head of four stroke piston combustion engines with a valve gear mechanism including lifting valves for each cylinder, especially to the arrangement of the conduits and valve gear elements in the cylinder head. Background of the invention From the present state of engineering it is obvious that for the valve arrangement of a four stroke engine the most suitable are the lifting valves. So far the best valve arrangement in the engine head is the multiple valve, mostly four valve arrangement. By this valve arrangement a part of the head surface is taken up by inlet valves and part by exhaust valves. It is that the passage through the conduits and arround the valves has a major influence on the engine characteristics. The cylinder head with inlet and exhaust valves is at the modern four stroke engines at the limit of passage capacity and further considerable increase can not be reached. The idea of using the cylinder head surface for the location of a common main conduit for inlet and exhaust from the cylinder has been known for a long time. This arrangement enables, theoretically, a considerable increase of passage capacity in the cylinder heads. The cross section of the main conduit may utilize up to 40 % of the cylinder cross section. But this brings a number of problems. For instance the necessity of further valve gear components of the inlet and exhaust conduits and their fifting to the main conduit, greater mass and a to large stroke necessary for the common lifting valve. The locating of the spark plug or jet injection nozzle may cause problems. But the main problems are the aerodynamic properties of the main conduit in head and the passage arround the valve. The design of the main conduit and lifting valve for inlet and exhaust of the cylinder causes a number of problems and the final features of known designs are, in general, worse than at the contemporary multi valve cylinder heads. Sumarv of the invention The above mentioned insufficiencies are eliminated by a greater extent by the use of a four stroke cylinder head with a gear mechanism with lifting valves according to the invention. The substance is that the least one inlet conduit and at least one exhaust conduit are joint into a single main conduit and that the inlet conduit is provided with a valve and/or a slide valve. The main conduit has at orifice into the cylinder a shape of an annulus, the axis of which is placed in the direction of the cylinder main axis. The orifice of the main conduit is provided with interior valve seat and exterior valve seat, inside which, at the closed position, is a ring plate of the single lift valve of the cylinder. The lift valve is provided with at least one valve stem. The size of the orifice passage section correspond with advantage to the sum of passage areas around and inside of the ring plate and at the same time the ratio of the inside diameter d^ v to the outer diameter d2 v of the ring plate corresponds with an advantage to the ratio of passage area inside the ring plate to the passage area outside the ring plate. The passage areas lie in this case in a plane normal to the cylinder axis. The sealing surfaces of the inside valve seat and the outside valve seat are preferably placed on a single flat or conical surface. The lifting valve may be provided with only one valve stem situated in the conduit axis, whereby the stem is connected to the ring plate by at least one bridge and is provided with individual sealing in the combustion engine head. The lifing valve may also be provided by two stems situated in the orifice of the main conduit whereby the stems are, in this case, situated on the ring plate at 180°. All stems may be arranged in one line one after the other. It is advantageous to govern them by a simple cam shaft. In the combustion engine inlet part a non-return lamellar valve or a : stating slide valve may be placed and in the combustion engine exhaust conduit a further slide valve, or other distribution element may be applied. In the orifice of the main conduit is favourably placed a low pressure fuel injection for the delivery of fuel directly into the cylinder space and the head is favourably provided with a collar for the safeguarding of shape transition from the outer valve seat to the cylinder wall. The collar may form a part of the head gasket. The inlet conduit may end on the same or on the opposite side of cylinder head compared with the exhaust conduit. The inlet and exhaust conduits may be thrown out of parallel to acomplish a turbulent effect. In the cylinder head is, according to the invention, appropriately placed a single main conduit of a great flow section, which is divided into a inlet conduit and an exhaust conduit. The annular shape of the main conduit and the shape of the ring plate of the lifting valve safeguard very good utilization of the main conduit cross-section and a uniform by-passing of the lifting valve with minimum of unwanted turbulance. The shape and dimensions of the lifting valve also safeguard a sufficiently large flow section on its outer and inner perimeter. All this leads to a considerable raising of parameters of the cylinder head. By this a higher efficiency, higher turnings and output of the combustion engine may be achieved. The shape of the main conduit orifice also enables the shaping of the inlet conduit and the main conduit for a purposeful turbulence of the intaken gas arround the cylinder axis at maintaining of sufficient gas inlet into the cylinder. This is advantageous for the improvement of efficiency and combustion ecology. The shape of the lifting valve and its situation enables a favourable shaping of the combustion chamber and suitable location of the spark plug or injection nozzle. From view of the heat load of the lifting valve and seats it is advantageous that the lifting valve actuated the exhaust and inlet into the cylinder. The inlet and exhaust system of a four stroke engine equipped by a cylinder head according to this invention must be designed with the requirement of a thorough scavenging of the main conduit at the end of the exhaust hub. This may cause certain problems especially with engines charged at atmospheric pressure. On these engines it seems to be advantageous to use a lamellar non-return valve in the inlet conduit and in the exhaust manifold an ejector combination of the branches. Advantage of scavenging of the main conduit is the coolign of the exposal cylinder head parts, of the lifting valve, valve seats and other parts. The injector delivers fuel directly into the cylinder through the space arising by opening of the lifting valve JThis arrangement is advantageous from the ecological view as the fuel does not form deposits on the conduit walls in cylinder head. In case that the sealing surfaces of interior valve seat and exterior valve seat are in one level, it is possible to grind the whole head including the sealing surfaces in one operation. A collar, which may be a part of the head sealing than forms an advantageous transition form between the valve seat and the cylinder wall. The cylinder head according to the invention is a solution which includes some elements not currently used in comtemporary cylinder head designs. But all these elements can be technically solved. Advantages and especially the prospect a further development of four stroke combustion engines should compensate the development expences and effort. Brief description of the drawings The cylinder head, according to the invention, will be described in more detail by individual examples shown on the following illustrations, where on Fig. 1 is the front sectional view of the cylinder head part with the main conduit and lifting valve with two stems according to the invention. On this Fig. 1 the main dimensions of the lifting valve, main conduit and engine cylinder are market. Fig. 2 shows a ground plan part of the Fig. 1. Fig. 3 shows an enlarged detail of the lifting valve and of the valve seat shown on Fig. 1. Fig. 4 is part of cylinder head with the main conduit and lifting valve provided by one stem in front sectional view. Fig. 5 shows a ground plan part of the Fig. 4. Fig. 6 shows a front sectional view of cylinder head of a four stroke engine according to the invention with a rotary slide valve in the inlet and exhaust conduit. Fig. 7 shows a ground plan of cylinder head from Fig. 6. Fig. 8 shows a front sectional view of cylinder head of a four stroke engine with a non-return lamellar valve in the inlet conduit and rotary slide valve in the exhaust conduit. Fig. 9 shows a front sectional view of the cylinder head of a four stroke engine with a non-return lamellar valve in the inlet conduit and a part of exhaust manifold adjoining to the exhaust port in the head. Fig. 10 shows the ground plan part of the cylinder head with symetrically spaced conduits, where the ' exhaust conduit outlet from the cylinder head is on the opposite side to the inlet conduit. Fig. 11 shows the ground plan of the cylinder head with inlet conduit out of parallel leading to the opposite side compared to the exhaust conduit. Fig. 12 shows the ground plan of the cylinder head part with inlet and exhaust conduits outlets leading to the same side of head. Detailed description of the preferred embodiments The model head 1_ of cylinder 2 of a four stroke combustion engine equiped with a valve gear with lifting valves 2 i n "the head 1. of cylinders 2 , shows on Fig. 1, is formed by main conduit 3., which has in its orifice 4_ leading into the cylinder 2 , an annulus cross-section. The axis 5. of the orifice 4, is situated in another axis 6. of cylinder 2. In orifice 4_ .of the main conduit 3. is situated the interior valve seat 8. and exterior valve seat £ whereby their sealing surfaces 10 are situated on one level. In this interior valve seat 8. and exterior valve seat £ is in the closed position an annular plate 12 of a single lifting valve 1_ in cylinder 2 - This lifting valve 7. is provided with two stems H leading through the orifice 4_ and these stems 11 are situated on the annular plate V2 at 180°. Fig. 1 shows also the main dimensions of orifice 4., lifting valve anα cylinder 2. For d-^ and d 2 the valid derived formulas are accourate sufficient. d 1 = l/3x + 1/6 V4x 2 + 6D 2 ; d 2 = (D 2 - 2d- L 2 )/2d 1 Vhere D is given and the dimension x must be suitably chosen. D is the diameter of cylinder 2 , d^ is the inside diameter of annulus of the main conduit 3. and d 2 is the outside diameter of main conduit 3., d vl is the inside diameter of annular plate JL2 and d v 2 is the outside diameter of annular plate 12. The execution of the sealing surface 10 of the exterior valve seat 9 is shown on Fig. 3. In another possible arrangement of head 1, according to Fig. 4, are the sealing surfaces 1J0 of interior valve seat 8. and exterior valve seat £ arranged so, that they are situated on one conical surface. The lifting valve 2 is provided by only one stem H, arranged on axis 5. of orifice 4_ and further axis 6. of cylinder 2 - This stem H is connected to annular plate 12 by three bridges 13 and is provided with sealing 14. The execution of head 1, according to Fig. 6, is based on the execution according to Fig. 1. The main conduit 3. is branchet into inlet conduit 15. and exhaust conduit 16,. The inlet conduit 15 is provided with a rotating slide valve 18 whose revolutions equal to 1/4 of engine shaft revolutions. The exhaust conduit 16 is provided with a further rotating slide valve 19. whose revolutions are also equal to 1/4 of engine revolutions. The execution of head 1 according to Fig. 8 differs from the previous execution according to Fig. 6 only by exchange of rotating slide valve 18 for a non-return lamellar valve 17. The execution of head 1 according to Fig. 9 is based on execution according to Fig. 6. The rotating slide valve 18 is replaced here by a non-retunr lamellar valve 1 and from the exhaust conduit 16 the rotating slide valve 1£ is entirely removed. The sealing surfaces 10. are situated on one conical surface. At all previous executions it is possible to place the inlet conduit 15. and exhaust conduit 16. in the head 1 of cylinder 2 according to Fig. 10, 11 or 12. Execution according to Fig. 10 provided a symmetrical inlet conduit 1_5 as well as exhaust conduit 16, while the inlet conduit 15 leads to the opposite side of head 1 than the exhaust conduit 16. Execution according to Fig. 11 differs from the execution according to Fig. 10 only by the inlet conduit 15 beeing out of parallel for the creation of a turbulence effect. On execution according to Fig. 12 both the inlet conduit 15. and exhaust conduit 16. lead to the same side of head 1 of cylinder 2 and both are out of parallel. The lifting valve 1_ in the head 1 of cylinder 2 opens and closes the orifice ;4 of the main conduit 3. leading to the cylinder 2 . At the beginning of the exhaust stroke the lifting valve is opened. In the main conduit 3. the inlet conduit 15 is closed by the rotating slide valve 18 or by a non-return valve 12 and in the exhaust conduit 16. is another rotating slide valve 1£ already sufficiently opened, while rotating slide valve 18 and another rotating slide valve 1£ have revolutions equal to 1/4 of the engine shaft revolutions. The flow of exhaust gases from the cylinder 2 into the exhaust conduit 16 starts. At the end of the exhaust stroke the lifting valve 2 ma y stay open or is beeing closed. In the inlet conduit 5 the rotating slide valve 18. or the non-return valve 7 is beeing opened. Followed by scavenging of the main conduit 3. space by clean air from the inlet conduit 15.. This is followed by closing of another rotating slide valve !£ in the exhaust conduit 16 by lifting valve 2 is open or beeing opened and the cylinder 2 is beeing filled. Further activity is similar to procedures at current four stroke engines. For the correct functioning of the engine a thorough scavenging of the main conduit 3. in head 1 at the end of exhaust stroke is necessary. From this point of view the use of a lamellar non-return valve 17 is an advantage, because it opens automatically and quickly to a great flow cross-section. It is also possible to have the head 1 of cylinder 2 without a further rotating slide valve !£ in the exhaust conduit 16. and to make full use of the exhaust gases intertia for the scavenging of the main conduit 3. space. For this purpose it is necessary to arrange usefully the exhaust conduit with ejector joints of the exhaust branches of each engine cylinder 2. At supercharged engine effective scavenging of main conduct 3. is no great problem. Industrial applicability The cylinder head described in the invention may be used with most types of four troke engines. Ve claim:

Claims: C L A I M S 1. The head of a four stroke combustion engine with a valve gear with lifting valves d e f i n e d by at least one inlet conduit (15) and at least one exhaust conduit (16) situated in head (1) of cylinder (2) joint into a single main conduit (3) and inlet conduit (15) provided with a valve (17) and/or slide valve (18) , where the main conduit (3) has at orifice (4) into cylinder (2) a section in shape of an annulus, the axis (5) of which is placed in the direction of the main axis (6) of cylinder (2) and orifice (4) of main conduit (3) is provided with an interior valve seat (8) and exterior valve seat (9) , in which, in the closed possition, is situated an annular plate (12) of the sole lifting valve (7) in cylinder (2) and the lifting valve (7) is provided with at least one stem (11). 2. Cylinder head according to claim l d e f i n e d by the size of orifice (4) flow-section corresponding to the sum of flow areas arround and inside an ular plate (12) and at the same time ratio of inside diameter -^ v to the outside diameter d 2y of annular plate (12) corresponds to the ratio of flow area inside annular plate (12) to flow area outside plate (12) , where the flow areas lies in a plane normal to the main axis (6) of cylinder (2) . 3. Cylinder head according to claim 1 or 2 d e f i n e d by that the lifting valve (7) which in its closed position is in the sealing surfaces (10) of the interior valve seat (8) and exterior valve seat (9) which are situated on a single flat or conical surface. 4. Cylinder head according to claim 1 , 2 or 3 d e f i n e d by that the lifting valve (7) is provided with only one stem (11) placed in axis (5) of main conduit (3) where stem (11) is connected to annular plate (12) by at least one bridge (13) and is provided with individual sealing (14) in head (1) of the combustion engine. 5. Cylinder head according to claim 1, 2 or 3 d e f i n e d by that the lifting valve (7) is provided by two stems (11) situated in orifice (4) of main conduit (3) , where stems (11) are on annular plate (12) placed at 180°, while all stems (11) in head (1) are situated in one row behind each other. 6. Cylinder head according to any above mentioned claims d e f i n e d by that valve (17) in the inlet conduit (15) of combustion engine head (1) is of automatic and non-return valve construction. 7. Cylinder head according to any above mentioned claims d e f i n e d by exhaust conduit (16) of combustion engine head (1) beeing equiped by additional slide valve (19) . 8. Cylinder head according to any above mentioned claims d e f i n e d by that in orifice (4) of main conduit (3) is an injector (21) for low pressure fuel injection delivery of fuel directly into the space of cylinder (2) . 9. Cylinder head according to any above mentioned claims d e f i n e d by exhaust conduit (16) beeing terminated on opposite side of head (1) than intake conduit (15) while axis of intake conduit (15) and/or axis of exhaust conduit (16) do not cross axis (6) of cylinder (2) . 10. Cylinder head according to any claim 1 to 8 d e f i n e d by intake conduit (15) and exhaust conduit (16) beeing terminated on one side of head (1) while axis of intake conduit (15) and/or axis of exhaust conduit (16) do not cross axis (6) of cylinder (2).

Inventors: KNOB VACLAV, KNOB, VACLAV
Applicants: KALIVODA ENG, KNOB VACLAV, KALIVODA ENGINEERING, KNOB, VACLAV
Application year: 1994
Main classification: F01L1
IPC codes: F01L1, F01L3, F02B75, F02F1, F16K1